


Re-training

by JellyFicsnFucks



Category: Undertale (Video Game)
Genre: Asphyxiation, Bathroom Sex, Bondage, Choking, Claiming, Collars, Consensual Sex, Knife Play, Master/Pet, Mating Cycles/In Heat, Omorashi, Orgasm Denial, Piss kink, Role Reversal, SELF FACIAL, Scent Marking, Tentacles, breath play
Language: English
Status: Completed
Published: 2019-01-23
Updated: 2019-01-23
Packaged: 2019-11-07 05:20:19
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 8,023
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17954336
Author URL: https://archiveofourown.org/users/JellyFicsnFucks/pseuds/JellyFicsnFucks
Summary: Papyrus turns around slowly, half caught with his hand down his pants, breathing hard when he whispers something so needy in his husky deep voice that Sans can’t help the shiver that runs up his spine.“ M-lorde… I… need. you. “





	Re-training

**Author's Note:**

> Sorry for being gone from this fandom for so long.  
> I've taken some stories with me when I left, so please excuse the mess while I re-upload old work. 
> 
> I'm really surprised to have a following of people who like my stuff, so thank you for the love and support. The messages I've gotten mean the world to me and it makes me terrified to let you down. ฅ(๑’Δ’๑) I'm really sorry to leave you hanging for so long.

It was the crack of dawn.

The artificial light of the underground hadn’t even grazed the homes of Snowdin yet Sans was wide awake. 

It was normal for him to wake at such an ungodly hour, rising before his alarm clock even began to relay the news of the underground. Listening to its song and updates were the peak of his day. He hears of more homicides in Hotland and a demonstration by Queen Toriel announced for tomorrow. The royal guard will have to step up to be prepared for that. 

Alpyhs, no doubt, had some stupid speech to prepare the lesser competent dogs to behave. It would be amusing to see the knight struggle to keep her position as vice captain. Besides, the lizard woman was far better informed than he would be, it might be a good refresher. He decides he should bring Papyrus along. 

He tilts his head to the wall separating their rooms, as if he could see his lazy brother still sleeping in. It wouldn't be a problem most days. In fact, Sans had gotten into the habit of letting his pet sleep. It made him an excellent guard dog at night. Which had its benefits… especially when lesser monsters tried to break into their house every other day. 

He clicks his tongue, quickly weighing his options… but he knew deep down he had no choice. The royal guards first and foremost duty lies in protecting the King and Queen. His brother could sleep later. 

He runs a hand through his closet deciding on what to wear… black and blue, black and red, black and purple… the ultimate decision was in intimidation. Which outfit would strike the most fear into his opponents? 

Certainly not the bunny costume hanging in the back of the shelf. 

He gets dressed, sliding on his long leather gloves and pulls on heels to make him seem taller. He fastens his belt and ties his scarf around his neck… to cover those non existent scars that made his brother jumpy. 

All dressed, he marches his way out into the hall and lingers to knock on Papyrus’ door. Its not such a difficult feat, yet part of him hesitates. Pap had enough night terrors as it was, a few more minutes might do him good while Sans makes breakfast or use the bathroom and brush his teeth…

A sound from the room proves him wrong. He perks up at the sound, his brother was awake for once but-

Moaning...

It didn't exactly sound like a royal guardsmen getting ready. 

Sans grimaces. He lays a gloved hand on the door knob and blows it open with his shoulder. 

“PAPYRUS~! YOU BETTER FUCKING PUT YOUR DICK AWAY AND GET READY OR-” 

He pauses,the words caught in his throat as his eye lights adjust to the dark room. The lights are off, yet the room is illuminated. Rather, the only source of light came from the orange glow dripping from his brothers face. His eyes, his nose, his tongue, his chest, wept the bright color of his bright magic. 

Papyrus turns around slowly, half caught with his hand down his pants, breathing hard when he whispers something so needy in his husky deep voice that Sans can’t help the shiver that runs up his spine. 

“ M-lorde… I… need. you. “ 

Sans covers his nasal cavity with a gloved hand, nearly smacking himself backwards in his rush. The scent alone was maddening, the look of another monster in heat was something insatiable. It smelled sickly sweet and standing in the room now it's clear the smell has clung to the clothes and sheets of his brothers nest. The scent of that spicy and sweet odor could drive monsters over the edge with lust. 

“Paps.” Sans watches as the warm syrup like glow drips over his brothers sternum. “You’re in no condition to leave the house. Stay here and sleep. I’m going out.” 

His brother fidgets in bed, trying to turn around and looks out over at sans from over his headboard. 

“But- you can’t … dont go. I need you. I need you so bad.” 

“I said I’m going. Thats final.” Sans rolls his eyes, he spots the pile of dirty laundry on the floor and backs away from the offensive pile. “I’ll be back home late. I permit you to go jerk off and leave me out of it.”

He had better things to do than to help his brother through his heat cycle. Though, he considers it a shame he wouldn't be able to watch his brother unravel in wanton cries of desperation and raspy need. Maybe he could tie him in the shed and have him wait for his master to come back from work. A couple hours without rubbing up against anything might completely break his brother, he’d be so eager to fuck when Sans returned. 

As he stares at Papyrus’ panting tongue he starts to think more and more this is a good idea. He takes back what he said before, Papyrus isn’t allowed to relieve his ache until Sans comes back home. He backs up towards the door, ready to head down and get his leash when he realises something odd. 

“Paps. Where’s your collar?” 

Papyrus’s face flushes darker than it had been. He looks down at himself, ashamed. His hips start to rock into the back of the headboard, tongue barely contained in his mouth. Rocking himself against the backboard with steady pounding and whines. 

Papyrus raises his eyebrows suggestively. 

 

“I can’t believe you.” Sans shakes his head, pressing his hand even harder against the inlet of his nose. “It's on your dick isnt it? Isn’t it! I hope it fucking snaps.” 

Papyrus hears none of this… still hungrily eyeing Sans from across the room. He continues absent mindedly thrusting up into the headboard for friction. A small whine in the back of his throat begs for Sans’ immediate attention. 

“Stupid.” Sans takes a step closer, removing the hand from his face and takes in a shallow breath of his brothers heat. It's a bit overbearing at first, smelling strongly of his brothers unique magic and sweat. He probably hadn’t slept at all. 

Sans takes his time, he pinches each fingertip of his left glove and pulls it off slowly to taunt the other. The he does the same with his right glove, letting Papyrus whine in need as his brother steps closer to him.

Each tap of his heels against the hardwood flooring makes Papyrus rock in place. His eyes follow the other as he edges around the mattress frame and leans in close. Close enough for them to be a hair width away from each other. Papyrus claws at the bedsheets between his thighs as his master whispered four clear words. 

“Lean back, filthy mutt.” 

Papyrus shivers, a bead of sweat running down his spine. Such demoralizing words made his bones ache. He wanted to jump up and grind up against the object of his desire, despite the clear demand given to him. 

A cold bare boney hand presses flat against his ribcage, helping guide Papyrus back into the pillows. He stares at the slender digits on his chest, tracing the hand upwards to look at the heated face of his master. 

He could reach up and kiss him. He wants to. Needs too.

To entangle their tongues and elicit a moan from his partner to make him feel as wrecked as he was in this moment. The orange organ protrudes from his mouth, trying to reach his master but all he can do is pant in the air like a puppy. 

Sans chuckles darkly to himself. His brother looked good like this. He’ll have to help him a little before work… especially since his brothers been so well behaved lately. He places a knee on the bed, his weight dipping the old mattress with a creak. 

His knees shuffle around, looking for a place to ground himself that isn't completely soaked. At last he takes a seat beside his brother, careful not to let any part of himself touch the other except for his hands.

He drags his index finger across the ribcage, swirling among the slick of magic like syrup bubbling under the surface. His pet is watching him, waiting for those fingers to dip lower. 

Sans chuckles, his voice sounding beside his brothers eardrum. The helpless, out of breath visage the taller presented him with was adorable. His pet is so eager for touch.

The way Paps ribcage heaved for shallow air. The way Paps hips rolled forward to thrust nothing. There is a small jingle of metal that sounds with every thrust Papyrus makes. 

Sans gives it a brief look, spotting the tight leather collar choked around his brothers phallus. The erect dick is already throbbing painfully, slicked and wet with his own juices. Sans makes a ‘tsk’ noise, returning to his brothers attention. 

“Are you already close, mutt?” He’s sure to draw his breath close to the cervical vertebrae, a sensitive spot that makes Papyrus shiver. The effect immediate, he bites his jaw together and heaves a harsh breath of air through his teeth. 

From where they had been stroking, Sans removes his hands and barely grazes the other with his touch. His fingers dance around each rib, barely touching the surface long enough for Papyrus to do anything but mew. Sans blows a little air on his neck, whispering darkly words of encouragement. “You didn’t answer pet.. Aren’t you a good boy? Speak.”

“YYEs.” Papyrus barely can catch his breath to respond. “Pleas... please touch me m-lorde!” His breath is in ragged pants.

At this point, Sans is more than intrigued. He sees the swelling of lust in the others eyes, smells it in the room. He sits by his brother, dragging featherlight touches across his ribs as the other squirms. 

“You didn’t touch yourself right? No one can touch you but me...”

Papyrus shakes his head quickly, his head arches into the back of a pillow and he winces his eyes shut. “N.. nuh… I…aah-- I waited.”

“And yet your collar is wrapped along your dick.”

“M-mlorde gave it to ---hmmf--- me!~” 

“Oh?” Sans smirks, feigning innocence even as he rubbed so lewdly at Papyrus’ spine. He pumps the lumbar nerves, kneading his thumb in between each joint. Papyrus lets out a shriek of pure bliss, he rocks his body off the bed, arching towards the feeling of his brothers deft hands when Sans stops. Its driving Papyrus mad. 

“So you’re grinding into the collar I gave you because it's the last thing I touched? So dirty…” He drones. 

Sans eyes the twitching member. With his brother on his back he can’t get much friction thrusting up into the air. The lack of attention is making him whine in sweet long melodic notes whales would most likely use to communicate. 

The thick magic pours out onto the bed, dripping from between his ribs and soaking into the fabric. He supposes he’d have to buy another after the mess Papyrus has made. 

He picks up his brothers hand, holding their phalanges close together for a moment, admiring the difference in the long slender digits his brother had. The ragged pained pants beneath him serve as a reminder of his needy pet. Surely he could wait a little longer, Sans was in the mood to tease him and hear those desperate mews for attention… but alas… he had to head for work and if Papyrus couldn’t go he would attend for both of them. 

He moves their hands together towards the source of Papyrus’ heat, enveloping his brothers hands around to pump at his own member. Papyrus sits up slightly to watch, his hand being guided up and down on his own shaft. 

The familiar sensation made foreign and erotic by having his brother pump him. 

“Nooooo…” Papyrus whines, even as his hips rock up to thrust into his palm. He turns his head to the right, to stare at the pensive Sans beside him. “Nng… I -hah .. I need you… PLease... aah~” 

The slickened wet sounds of his magic slapping against his cock fills the air. Rushed and desperate in rhythm with his own jerking off the bed.

Sans smirks, watching his pet writhe in agony. 

“I have work Papy.” He whispers, placing a chaste skeleton kiss upon his head. “Can’t have you getting my hands dirty... “ He places his hand over his brothers and jerks him quickly. 

“Don’t.. Ah.. Dont go to wouurk…hn.” His brother moans, he starts to pump his own member, feverishly driving a quicker pace. But its not enough, he slips his hands from Sans and switches their order, guiding Sans to pump him with an intense need. The drizzle of precum coats their fingers. 

“Stop.” Sans tries to pull his arms away. “You’re getting your filthy seed on my hand mutt!” He pulls his arm again but Papyrus has their fingers intertwined, stroking himself to his brothers yelling. 

Sans sits up straight, presuming his authority over his brother. … The mangy mutt seems to forget whos in control here. “Let go, mutt.” He snarls. 

“Haaa~ but… Sans…I -” 

“Sans?” Something suddenly snaps in him. He grips the others neck in a chokehold. “You don’t get to call me Sans, understand mutt?!” He presses his phalanges deeper into his throat, trying to act threatening but loosens his grip at once. Appalled by the strangled moaning coming from Papyrus.

He… enjoyed this?

A sickly moist feeling drips through his other hand.

Papyrus came. 

The stain of orange magic drips between his bones, his own hand and his brothers are still connected. 

“Well I hope you enjoyed yourself, freak.” He struggles for control of his hand again, but Papyrus lets him go with a satisfied look on his face. Sans sits back on the bed, staring at his brothers long tongue, the orange magic whipping about his soul convulses and splatters the sheets. 

Sans looks down at his right hand, the heated magic drips down, rolling towards his elbow before he tries to wipe it off on the sheets. The color doesn't fade, the orange tint of ecto cum shines through on his pale white bones… This fucking mutt, marking him on a weekday… 

“Now I have to wash up too? I haven’t even gone to the bathroom! Or made breakfast! I swear Paps, if I’m late to this meeting because of you I’ll cut off your dick!” 

He slides down from the bed, holding his arm as far away from his clothes as possible and navigates his way out the bedroom, watching his footing over books left out, avoiding the pile of dirty clothes. He marches out into the hall and straight over to the bathroom where he starts the sink. 

There's a strong difference in atmosphere from the bedroom to the bathroom. For one, the pungent odor and heat from the other has no bearing in the bathroom. The place only smells of fresh soap and the tiled floors hold the chill from the night. It feels sanitary, unlike the slovenly rat nest his brother called a room. He grabs the bar of soap and starts to lather it up to scrub at his bones.

Fuck, if the guard caught sight of that orange stain on him or his clothes he’d be screwed. The dogs already had a sharp sense of smell as it was. For the most part he could say he smelled like Papyrus because he lived with him, vice versa but the dogs could catch the scent of seamen in the air… they were especially judgemental about the brothers. 

Not that Sans ever asked for their opinion, but reeking of his pets seamen did not seem like the best way to start the day. 

He barely hears the pitter patter of bones linger in the doorway, he doesn't turn his head to look. Instead he stares at the reflection of the mirror. His brother stands half bowed, his arms across his chest as though he were chilly. He certainly shakes like that was the case. 

“Came to apologize?” Sans asks. He scrubs at the length of his arm, still spotting the orange hue of magic caked to his bones. He glances at the mirror, Papyrus certainly seems apologetic. His eyes are downcast and he seems scared to come in the room. But more than that he looks… unsatisfied. 

What? Did he want to hug or some shit? Sans didn't have time for ‘tlc’ right now… especially when he had already spent so much time on tending to this heat issue. 

It looks like Papyrus has found a pair of boxers to wear, so that he doesn't run naked in his house… though it wouldn’t make much difference. He’s left a trail of seed seeping down his leg, it clings to the carpet in the hallway. 

That will be a pain to clean...Sans grimaces. He can do it when he gets back. 

He notices in Papyrus’ hands is the leather collar, he holds it with some apprehension. It seems to be the source of his pets quietness. Sans runs the hot water over the length of his arm, satisfied with himself being clean he moves aside, offering the sink to Papyrus. 

“Do you want to wash it?” He looks over his shoulder. Papyrus nods. 

Impishly he patters into the bathroom and looks away from Sans as he uses the sink. 

“You want to talk about the choking thing Paps?...” There's an awkward attempt at conversation for a moment. Sans grabs his toothbrush and begins his daily ritual of getting ready. Perched on the edge of the bathtub rim, Sans waits for some sort of response. 

The muted sound of running water fills the place of silence between them. Papyrus focusses on cleaning his precious collar, feeling some regret for not taking care of it. As soon as it's clean he places the damp thing back around his neck and clasps it tight.

He takes a step back towards the door, putting enough space between him and Sans to represent respect. Especially after he had broken his brothers command earlier. Sans appreciates that. He had trained his mutt at least to know when he was wrong… He can excuse his actions up until that point as something he did in his frenzy of heat. 

Speaking of which, though the glow doesn't shine as brightly in the well lit bathroom, it still glows from under his black tank top. His heat had not settled at all...

“We…” There's a careful pause in Papyrus’ words. Its rare he speaks his mind… “We sleep in different rooms.” 

The statement is so simple Sans has to wonder what, if any, cryptic underlying message the other is trying to convey. He turns his back on Papyrus and spits and rinses in the sink, plopping the toothbrush back where it started. Before he can ask, his pet continues. 

“You used to sit by me when I have my nightmares… I used to be your pillow when you took a nap… we used to… spoon.”

“Stars Papy, you’re so fucking sentimental… I have to piss. Get out.” 

“I mean… we don’t spend any time together anymore. We’re awake at different times… we eat different meals alone... and I really want to touch you.” He takes a step forward, closing the door behind him and locks it.

“Feeling bold today, mutt?” Sans scowls, pulling a towel down from the rack he pats dry his chin and hands. “And what’s this have to do with your incident earlier?”

“I…” The blush on his cheeks grows a little brighter, Sans can’t tell if it's because of his pets growing arousal or because of embarrassment. “ I... like it. Mlord.” 

“I figured as much… I’m kinkshaming you.” An elongated finger points at the door, Sans motions at it with a sigh. “Now seriously Pap, get out. “

Papyrus does not move. 

“Pap? I said get out.” 

“Why?”

“I have to get ready for the guard. Its only Tuesday.” 

“I know… I mean… why do I have to leave?”

“Cuz I have to take a leak!”

“Yeah… its not like I haven’t seen it before.” 

“...”

The glow of magic still blares brightly under Papyrus’ clothes. Any semblance of restraint he had from cuming a moment ago is slowly being pulled away. There’s a hunger in his eyes, a search for something more as he undresses Sans with his eyes. 

“...You’re really kind of a freak aren’t you?” Sans whispers. “But, there's no show for you, Pap.” He raises his hand, calling on his magic to help unlock the door from this distance. “Now get out before I kick you out.”

The solid resounding click of the lock being pulled back has the same sound of a loaded gun barrel. Paired with Sans’ words it acts as a warning that Papyrus takes no heed too. 

He steps forward, crossing the small distance in the bathroom with ease. Seizing one of Sans hand in one his own he looks deep into the skeletons shallow eyes. The dark pools of black behind those flickering eyelights intrigues Papyrus. He wants to bend to his brothers height and lay a kiss on the edge of his eye. He wants to stick his tongue around the ring of bone and fuck the space between his skull and the void of magic in his being. 

Papyrus brings his mouth down to clank against his brothers, wanting so much more than the brief kiss a skeleton can offer. He tries to draw his tongue past Sans’s mouth and taste him from the inside out. 

Sans stands firm. Adamant. 

He doesn't open his jaw, instead clenching his teeth tighter as his pet nibbles and laps at his mouth. At first, he had been shocked his brother pressed on despite his clear orders but it was increasingly obvious, ( so much so that he can feel it against his hips) that Papyrus wasn’t thinking with his head… but instead was thinking with his head. 

Sans growls. With his free hand he makes the motion to summon a femur to his aid. Papyrus was stronger than him only in sheer brute force. Unfortunately that was the only way to make his pet listen as well. 

He presses the femur against his brother's throat, stilling his actions as Papyrus recognizes the hum of magic so close to him. 

“Don’t make me whittle down your health Papyrus…” Yet another warning Papyrus ignores. 

He fights Sans for control, ignoring the attack raised at his health.

“You wouldn't hurt me… mlorde.” Papyrus snickers. He palms the red attack and pushes it aside with ease, exposing his brother for the softy they both knew he really was. Sans grimaces. Papyrus was right… he couldn't… wouldn't attack him with magic. But hell, he had trained this despicable mutt this far along without the need for it. 

Sans sinks to the floor like a rock and aims a kick right at Papyrus’ shin. The taller monster yells out, stuttering a curse of pain and topples forwards into the bath. He rips the shower curtain on his descent, banging his jaw on the tub. The thunk of both metal and bone makes him cringe into himself. 

“Sorry Pap, I warned you but you just didn-” He makes to stand up again but Papyrus still hasn’t loosened his grip on Sans’s arm. Instead it just tightens. Papyrus turns his head to Sans slowly, a little blood spills out from a chip in his jaw. His right eye is engulfed in flame. His magic whips around the single eyelight. 

His brother oozed nothing but malice in that moment. Something of fear that made Sans’ legs feel like jelly in his high heeled boots. He’d never seen Paps so fierce. The goofy crooked smile on his face that once begged for his master to walk slower as Sans pulled his leash… the warm child like smile Papyrus made when he ate something that tasted sweet and he’d hum happily in his chair swinging his legs out… the content pull at his jaw when he saw Sans return from work and enveloped him in a hug… The warmth of a genuine smile was completely gone. Papyrus looks like a seasoned warrior. One seeking revenge. 

Sans was scared.

Papyrus wipes at his jaw, seeing the color of blood on his wrist. He licks at the wound, eyes turning towards Sans at once. His grip gets tighter, Sans stifles a grunt of pain. When was the last time Papyrus had such a strong presence?

“Piss or cum” Papyrus growls. 

To which Sans replies. “ Wha?” He was sure Paps was out for blood. 

“Piss or cum? “ Papyrus repeats. “Either way, I’ll force it out of you…” 

A whip of orange magic stretches out for Sans yanking his wrist forward. Sans gasps, he stares at the tendril of magic. What the hell was this? His brother comes close to him, pressing his teeth against the nape of his neck. Biting down. 

His hands dip underneath his shirt, lovingly stroking his spine. Sans bucks up in the sudden touch. His bones sensitive to the rough pressure his pet starts with. 

A tendril of magic wraps up his femur. Another wriggles between his spine. Coiling and flexing… at the same time Papyrus starts to unzip his brothers pants, rubbing his bones to incite his magic to form. Sans shudders. He feels his magic try to take form but he he restrains himself. His knees buckle under the wave of pressure from both behind and infront of him. 

How had he never known his brothers magic could do this? Why was he so turned on by his brothers authoritative voice. Had Paps ever done something for himself? 

“Hows that Sans?” The murmur by his collar makes Sans whine. He unwillingly bucks his hips as the worm like magic spreads over his iliac crest, pressing flat against his inner bones. 

“Im gonna kill you..” He gasps.

“I love you” Papyrus murmurs. 

He’s all that Sans smells, the sweat of his body, the smell of his cum, the scent of that sickly spicy honey musk of magic… Sans drifts his eyes closed, letting his weight fall into his brothers waiting arms. He makes a stunted whine in his throat as a thumb rub across his aching member. He can’t hold back his magic anymore and the soft glow of his own need starts to come into shape. 

“ No. ‘m goin… to be late.” He whines. He feels his brothers hot breath on his neck. The pleasure hasn’t completely clouded his mind. He tries to push back against the figure in front of him. He presses his palms into the groove of bone on either side and slides back only to feel the slick wetness of a tendril of magic scraping up beside his saccram. 

“I’m gonna be late Paps. Stop.”

“Then just cum already.” 

Sans lets out a murmured whine he presses it against his own shoulder, trying to cover the cry. 

“Its not funny Pap. I have to … have to piss.” 

Bucking hips. The worming tendril of magic feels slick, wet inside him. Its slimy and able to fit between his ribs and fit into the gaps of his ischium and up his leg. His clothes are soaked. His pants are at his knees as Papyrus rubs him closer and closer to release. 

Sans tries to push back again, rotating his hand to test how tight his bonds were. His brothers hands had been replaced by the magic that flowed out from his soul. The orange whips of glowing ecto magic surround Sans and Papyrus as he controls them. 

Paps fingers finally start to slicken against Sans formed cock. He moans at the contact, trying to will his arousal away… but Papyrus won't let him go that easily. 

He starts to harshly pump at the organ, making Sans hiss in pain and bend forward into the open arms.”Paps… “ Sans is in tears. “Stop… It's not sexy… I just .. I just really have to piss.” He can’t help the moan that rips through his rib cage, a worm slithers across his soul. 

“Its okay. Shh… just do it...“

“No.. I dont want … dont want to… on the floor.” 

“Oh? Is that the problem?”

The feverish movements stop. The tendrils of magic that had been massaging across his bones deflate and disappear leaving only sticky trails of orange magic in their place. Papyrus stops jerking him and stands up, yanking with him Sans arm. Sans goes limp in the touch barely able to keep himself right and his eyes open. 

He’s bent over the toilet, with his hands crossed on top of the tank to keep him upright. Papyrus kicks his legs on either side, making his stance wide as he bends him over the toilet seat. 

“Better? Mlord?” He murmurs against his spine. “Now you won't make a mess on the floor…” 

Sans flushes he looks down at his limp dick dangling over the toilet bowl. He shudders. His whole body feels hot and yet cool. The heat of his brothers slick ecto juices cool quickly in the bathroom air. His clothes are ruined… drenched… his armor has been shed.. His pants are rolled up at one ankle and he’s bent over to wait for Papyrus again. 

Since when did Papyrus make him feel so helpless? It shouldn’t be this way… his brother was his pet… not the other way around! And yet he whimpers. Shaking like a puppy in the cold. 

Papyrus’ warm embrace envelops his slender frame easily, he feels a thick cock sliding up and down his saccram. The hands return, pumpin intensifies across both his spine and his weeping member.  
Sans cries out as he feels the heated cock start to enter him. He knocks over small decorative glass bottles lined across the back of the toilet tank. Some clatter to the ground. Others smash against the tile, spraying their contents and glass shards across the floor. 

“You fucking muuuuuhhhhh tt~ “ He whines. He trembles with his legs spread on the tiled floor.The heels have no grip on the tile, he feels himself sliding and tries to stand on his toes to meet with Papyrus’ thrust. But it doesn't come. The throbbing cock slides out and rubs against Sans’ spine. Dripping through each crevice of bone. 

Sans shivered in ecstasy… he’s never subbed. Never known how exciting his brothers hardened gaze could be… how forceful Papyrus could command him and make him want to scream and beg to be touched. He’d never admit it… but he wants that thick slab of meat back inside of him, not sliding over his spine like a tease… 

Then theres that pressing pain of his bladder. Papyrus slows his rhythm, only rubbing against his growing need. 

“Tell me you want it…” The whisper echoes through Sans’ bones. He yearns to be touched. The closeness is driving him crazy. He shakes his head, no. He wouldn’t beg. He’d never beg. Because there was no way he was going to bend to his brothers cock. 

He was Sans. The Magnificent and Terrifying Sans! He’d never-!

“AAAAAaahaa~ Ah~ PApppy~!!” A cock slams into Sans, grinding up against his spine and thrusts again up into the pool of heated ecto flesh. Sans gapes like a fish for air. He can’t take it. His hips buckle and the long stream of urine starts to pittle against the toilet seat- completely missing the bowl. 

Pap lay buried deep inside him, rocking gently while whispering hot words by his spine. Sans arches in release. His whole body tensing up… he slides on the floor, his legs feeling weak but he’s skewered between the Papyrus cock and the toilet seat and it keeps him slightly upright. 

“Good boy…” Papyrus whispers.

No this was wrong. Sans cries. He can’t stop pissing. “Auaa~” It feels so good, to just let go, The coil in his chest relieved. “Haagh…” 

But it was wrong. He was pissing in front of his brother…”Ssto-” and and he wasn’t a good boy. He wasnt a pet, he was a master. He wouldnt…”Nnno…” woulnt be… “... hnngg~….” a mutt. 

“Wowie…. You really made a big mess Sans… But now I want to make you cum... “ A sharp thrust makes Sans mind go numb. He rocks forward, banging his head against the bathroom wall. His toes arch off the ground, searching for a place to stand. 

No. No. No. He wouldn't. --Even if it feels good.  
He wouldn't…-- he's late. A fucking mutt… --- making him feel like this… was… 

“Knnnow. Know Your p-p-place! Mutt!” Sans pants. He reaches an arm back and grabs the mound of flesh thrusting into him. Papyrus whines, jerking his hips up but he can’t seek that warmth inside of the other. Sans jerks away, his bucking hips collapse and he falls onto the seat, kicking backwards to make Papyrus fall too. 

They both sit for a while. Papyrus on the floor, Sans on the toilet seat, catching their breath as their gaze is shifted only on each other. 

Sans wipes the drool from his mouth. His ears are ringing and his chest is rising and falling heavily. He pulls his shirt down… a futile attempt to hide himself considering the soaked shirt accentuates every rib and bone. 

“Dammit Paps. What's gotten into you?”

“...” 

“I’m…” He hisses for air. Trying not to let his voice whine as he speaks. “I’m going to work! You’re going to stay home! Go fuck off until your dust!” 

Papyrus seems to do just that… Denied his chance to cum a moment ago, he starts to work up his penis again, laying his head back against the tile and moaning so loudly Sans blushes. Papyrus was giving him quite a show…. Not even hesitating or embarrassed. 

Sans tries to stand again, his heels slip out again but he throws up his hands to prevent himself from falling. He feels Papyrus’s eyes watching his every move, his raspy panting following each tacit movement Sans makes. 

“Wow you're really pathetic…” Sans murmurs. He’d never seen his brother in heat before. His own heat wasn't nearly as bad. He had self control… but all of that means shit when he looks down on his beloved brother wanking off. It was thrilling. 

Fuck. He wasn’t going to bottom, but gods was it tormenting him to watch his brother shamefully jerking himself raw. A vein runs up the side of his shaft, throbbing painfully with the need to cum. Paps just can’t get the gratification he wants.

Sans is still burning with embarrassment. He can’t help his own arousal, the feeling of Paps dominating over him was… exciting. 

 

 

He looks down at himself, covered in his brother juices. The tentacles had ravished him and left a jam all over his body. A damp wet smell of magical ecto magic was soaked into his clothes, crusting in the dry air. 

Forget the guard, Sans couldn't even step out the house like this… these clothes were ruined Sans was an absolute mess of cum tears and snot. The dogs could probably smell the magic staining him a mile a way. Probably further than that… 

And then there was his pet. Lying on the floor moaning… delightfully ignorant to the humiliation Sans would have to endure if he went to the guard like this. If his pet had just obeyed him he could have left the house already! His pup had to be retrained. There's no way he can just let his brother think it’s okay to just bend him over like some fucking toy. He was already running late, he could shower and show up an hour late. The guard didn't fucking matter anymore. He had to teach Papyrus a lesson. 

“Ive changed my mind, Pappy.” Sans squats down, the word Pappy feels so sour on his lips. Orange eyelights follow him as he descends down to the bathroom floor with his brother. Papyrus is out of breath but so goddamn needy. 

“I’m gonna stay home.” Sans says sweetly. Syrup like magic drips past his coccyx. The secretion stretches slowly down to meet the floor. Papyrus’s eyes follow it, then flicker up back at Sans as he continues his rant. “And you're gonna tell me just who the fuck owns you, right mutt?” 

“ wuff.” 

Sans chuckles darkly, taking that as consent for what he’s about to do next. He brings both his hands to the back of his neck to untie the scarf he wore. This time there isn't the strike of fear that passes Papyrus at the sight of his bare neck. Instead Papyrus lunges forward, compelled to lap at the pale milky bone just hidden under the surface. 

Sans punches him, striking the side of his skull with a closed fist. “Did I say you could move?” He grimaces, one of his eyes twitches in anger. All his hard work training this mangy mutt had been undone in one day. He takes his scarf and ties it around his brother's hands, looping the longer ends through the gap in both his radius and ulna. 

Papyrus shivers, eager to play this game. All day he has been waiting…. Aching for his brothers touch. He pants for air, tracing the boney fingers that run over his ribs Sans grips the base of his cock. Papyrus moans, urgently thrusting his hips up when Sans tightens his grip. Painfully so. He can’t get off like this. He can’t even move. 

He needed more. He lazily lifts an eye to his brother, whimpering like the filthy animal he was. Begging quietly for some answer. 

“You like choking right?” Sans snarls. He squeezes his claws deeper into the flesh, eliciting a pained whimper. “I’ll show you just who the fuck is in control here.” Sans pulls at his scarf, making sure his brother was bound so tightly he couldn't fight back. All that was left was the issue of his magic. That was easy.

Sans had control again. 

Taking control and instilling fear was easy. He brushes his fingertips against the glass shards on the floor, palming one and presses the sharp end of it into the tip of his brothers urethra. 

“ If you summon your …octopus magic thing… even once…. I’ll cut off your dick. Got it mutt?”  
Papyrus nods again and again. Not saying any words. Their roles had shifted and his masochistic brother loved to be ordered… 

Sans kicks off what remains of his pants, dressed only in a wet tshirt and boots he positions himself between his brother, drawing Papyrus’s legs up on top of his shoulders. 

“You’ve been so naughty… begging for a fuck haven't you? Even disobeying me Paps. What a bad boy.” 

Papyrus nods his head, clearly not grasping the shit load of trouble he’s in. His eyes are only transfixed on his brothers own glowing member as he slides it alongside his own erection. Sans releases his grip on his swelling cock, satisfied with that response. He rocks his hips into the bother, frotting against the heat of his magic. 

Where their magic collides it creates a new color between the two of them. There is a froth that starts to build up between their rocking. Papyrus moans. Wanting more than just the slippery feeling of his cock sliding along his brothers. Sans can tell, his pace quickening as he hurries to drive his brother over the edge. 

“You’ve covered me in your filthy magic, So I’ll have to fill you with mine.” He pants. He thrusts up again, prodding at his pelvis with a sharp thrust.

Papyrus whines, his body shaking. Worked up, he draws his hips forward, trying to pull Sans into him, unsatisfied with just rubbing up against the other. He wanted to kiss Sans, bend up into his touch and cry out as Sans devoured him like when they used to fuck before their bedrooms had been split up.

Sans watches carefully. His brothers erect cock, overflowing with milky precum that causes wet slapping noises every time their hips meet. He’s careful not to let Papyrus draw him in, he doesn't want to reward his pup just yet. 

Instead he turns his head to right and bites down on the inner thigh hung over his shoulder. Papyrus breathes sharply through his mouth, tongue hanging on the border of his bottom teeth. Their hips rut into each other a few more times, eliciting a louder and louder moan from his brother. 

“You okay bro~?” Sans teases. “Do you want me to stop?” He summons his tongue to lap at the tender bite he’s taken in bone. He stops moving, even as Papyrus wriggles beneath him, begging. 

“ Fuuh--- Fuuuck no… Hahh... “ He gasps, “I waan” He moans, still greedily thrusting his hips up, searching for pleasure. “ I want. ~ hnnng ~ need you to f-f-fuck me ~aaahp”. His mouth drools as he speaks, and he chokes on his own spittle. Coughing up onto his side... 

Sans can’t keep his cool after such a needy confession. He rams into his brother, impaling the soft ecto flesh with his own magic. Breathless, at the scene presented before him.

Papyrus’s quivering hips shake his entire body. He openly gasps for air, wailing in pleasure. Sweat slickened down his brow and calling for Sans in such a sweet wanton voice. His shirt, the floor, and Sans are all soaked in his juices . Sans hates that. He needs to leave his own mark. 

He bends down to nip at his brothers shirt, pulling it up to expose the creamy half melted soul in his rib cage. That was the source of all of this. The fucking reason he was late to work and had to appease his brothers horrible heat.

He reaches for it, palms it between his index and thumb. 

He drives his hips up into Papyrus again, raking his body with stimulation. Sans had a strong urge to just leave his brother half fucked up like this. It would teach him a lesson for being so disobedient. 

He rubs over the tender soul with a thumb, feeling it pounding against the pad of his fingertip. He’d never hurt his brother…and yet it's exhilarating to know that just a taught squeeze was all that stood in his way of ending his mutts miserable existence. Papyrus knew it too, he tilts his head up from the tiled floor, cautiously eyeing his soul as it leaked down Sans arm. 

The ooze drew from it landed between the heat of their pelvis, slickening the opening even more for Sans to bury his bone into. He aims his thrust up at the base of Papyrus’s spine, earning a surprised yelp every time he slammed into that spot. 

With his other hand he lifts Paps leg higher and slams into him again, pushing him up against the tub so that every time he plunged into the warmth gelatin depths of his brothers heat he’d smack the back of his skull flat against the metal. 

“Fuckig mutt.” Sans pants. He draws his tongue to lap at the floating soul in his grip. Papyrus cries out, horrified the sound even came from him. He sees stars. He stares out at Sans, vision clouded by the constant contact his skull made with the metal and the sudden wet lick that fondled his soul. He rolls his spine forward and tries to sit up, wanting to watch his big brother impale him with every thrust bringing him closer and closer to something… 

Something he couldn't tell, he felt like he was going to black out from the pain and pleasure assaulting his senses. 

“Don't you dare... fall asleep here you lazy fuck.” Sans purrs. He bends Papyrus over, drawing his legs above his head as he drives deeper into him. Papyrus can’t hold on much longer. Sans already knows that. He lets go of Paps soul in favor to stroke at his brother's length. He aims it right at his panting face. Paps mouth is open breathing hard , begging for release, he only barely recognises his body being contorted to cum on himself. 

“N.nn oo~ aaa” He can barely hold on when Sans crashes their hips together, whispering in a voice so silky deep that Papyrus twitches in perverse need. 

“I own you, mutt.” 

With a cry in agony Papyrus squeezes his hips down and releases his seed over himself. It drenches his face. Dripping across his frontal lobe, spraying over the nape of his neck, and dribbles into the rim of his eye. He convulses trying to catch some air while the trickle of sperm overflows through his ribcage, his soul gushing at his release, marking his bones with the secretion of his own magic. 

Sans huffs, not slowing his pace in the slightest as he watches his spent brother gag for air. He won't allow his pet even a moment of rest. His brother truly needs to writhe in agony for Sans to forgive him. 

He grinds his hips down into Pap, hurriedly thrashing, thrusting inside him to warp and twist his insides. Paps walls were already clinging down on him, sloppy juices bleed from him. His brother is begging for him to stop. Whining as he slams his flesh deep inside him and makes his pet spasm with another orgasm. Mercilessly submerging his rod again and again into his brothers wet chasm. 

Papyrus lashes out, throwing his tied hands up to wrestle away from the ripple of pleasure that echoes through his bones. 

Sans pushes him down, smashing his head against the cold tiled floor.

Papyrus thrashes out a couple more times, weak as his body spasms again.. Unable to cum, drained completely of energy. He whimpers as Sans spills inside of him, his stream stretches the ecto body out, filling Paps with the warm slosh of seamen that erupts from Sans. They sway a few more times together, riding out the depraved orgasm Sans wretched from his entire body.

When they stop moving Papyrus gulps dryly.Tongue lazily drifting over the metal of his tooth and tasting his own cum mixed with his saliva. His throat feels so dry.. So raw from begging and screaming. 

Both of his knees are lowered and Paps swears he can immediately feel the pain in his spine from being arched and fucked into the floor. He feels tears stream down his face and the wet of his soaked shirt and the muddy floor seeping through his bones. 

His insides twitch. He can’t dismiss his magic with his brothers seed still inside of him and despite how he wants to turn to his side and vomit he can't because Sans is still buried inside of him. Panting hard and fidgeting.

“M… mlord” Papyrus struggles to speak. He wants to close his eyes and let his body rest after such a mind blowing fuck. “I’ll b-b-e good. I’m sorry. Sorry.” He cries. He draws his scarf tied hands to his face, trying to wipe at his tears and clear his face from the unbearable drip that runs into his eye sockets. He has trouble focussing his eyelights to look at Sans. “I’m sorry.” He pants again. The words feel numb in his mouth. His throat hurts from screaming. 

Sans bends down, pulling a towel from the rack as he does so and rubs it gently across Papyrus’s bottom jaw. Cleaning him up, just enough to plant a kiss between the two. Something Papyrus has been aching for since they started and now can’t even properly draw his tongue up to meet Sans. 

“It's okay, Pap.” Sans whispers. “I forgive you.” 

He pulls back again, grabbing Papyrus’s hips to pull himself out. His seed spills out onto the floor, leaking from his brothers stomach. Rightfully marking his property. 

“Now Papy,” He whispers. He bends down for another chaste kiss from his spent lover. He lets a smirk fall across his face.

“...are you ready for round two?”


End file.
